Computer-aided design (CAD) and computer-aided manufacturing (CAM) tools have been in existence for many years, and have been extensively applied in the manufacturing industry. CAD software may be used to create three-dimensional models of mechanical parts (e.g., shafts, gears, turbine blades, etc.). These models may be referred to as CAD design models. CAM software may use CAD design models to generate process plans, which may include control instructions for driving equipment that is used to manufacture the parts. Sometimes CAD software and CAM software are used as separate components, while sometimes CAM software is integrated within a CAD system.
In many factories, mechanical parts require a sequence of manufacturing steps (e.g., rough machining, finish machining, inspection, grinding, polishing, etc.) to make a part within tolerance. During an N-step manufacturing process, the parts produced may not experience significant change in form or feature, but successive steps of the process can accumulate errors in part dimensions. Managing these errors can be quite important, particularly when these parts are components of an assembly or product (e.g., an engine).
At any point in an N-step manufacturing process, the accumulated errors thus far in the process sequence may cause the process planning of the next step to be adjusted (re-planned) to keep the part within its allowable total tolerance envelope. Sometimes this may require the geometry to be modified slightly using the geometry parameters. Presently, it is common practice to generate a new CAD design model and new process plans at each step of the manufacturing process. The CAD design model that is generated for a particular step of the manufacturing process reflects the dimensions of the part at that point in the manufacturing process. The CAD design model that is generated for a particular step is then used to generate new process plans appropriate to the equipment that will be used for that step of the manufacturing process.